Plural lamps for simulating a candle flame



March 25, 1969 P. J. KAYATT PLURAL LAMPS FOR SIMULATING A CANDLE FLAMEFiled Sept. 17, 1965 INVENTOR. Rf/JP 4Z ZQYTI' United States Patent O M3,435,286 PLURAL LAMPS FOR SIMULATING A CANDLE FLAME Philip J. Kayatt,Bronx, N.Y., assignor to Duro-Test Cor- ]orallion, North Bergen, NJ., acorporation of New Filed Sept. 17, 1965, Ser. No. 488,117 Int. Cl. H01j1/00; H01k 1/14 U.S. Cl. 315-47 8 Claims ABSTRACT F THE DISCLOSURE Thepresent invention relates to light sources of the incandescent filamenttype which simulate the flickering illumination of a candle.

The device comprises at least two light sources one of which is steadyand the other of which changes its intensity periodically at a frequencywhich approximates rthe flicker frequency of a candle. Such a frequencyis in the range from one to ten cycles per second and preferably aboutthree or four cycles per second. A combination of three light sources ofwhich one is steady and the other two of which change their intensitiesat different repetition rates will produce a very satisfactorysimulation of a candle. The incandescent filaments may be formed eitherof tungsten or carbon. The non-steady filaments are flashed bythermosensitive switch elements in conventional manner and the switchingmay be either to fully ofi or partially ofi, as circumstances may renderpreferable.

The filaments may be enclosed in a common evacuated glass envelope or inindividual envelopes. Additionally, a translucent flame-shaped coveringformed of a suitable plastic applied to the common envelope or the groupof individually enclosed light sources will prevent direct observationof the filaments and enhance the simulation of an actual candle flame.

Various objects, features and advantages of the invention will becomeapparent upon reading the following specification with reference to theaccompanying drawing forming a part hereof.

Referring to the drawing:

FIGURE 1 is a side elevational view of a lamp embodying the invention.

FIGURE 2 is an enlarged elevational View partly broken away and shown insection taken along the line 2f-2 of FIG. 1.

FIGURE 3 is a schematic view of the lamp shown in FIGS. 1 and 2illustrating the electrical circuitry.

FIGURE 4 is a view similar to FIG. 3 showing a modification in which allof the light sources are enclosed in a common glass envelope.

Referring to the drawing, the lamp designated generally as comprises aflame-shaped covering 11 formed of a translucent plastic material suchas a silicone rubber which may be conveniently applied as by dipping,for example. Molding and other techniques may be employed -wheresuitable. The lamp is shown provided with the usual screw-type base 12for insertion in a complementary socket (not shown) connected to asuitable power supply.

In the embodiment shown in FIGS. 2 and 3, light sources 14, 15 and 16are enclosed in individual en- 3,435,286 Patented Mar. 25, 1969 velopes17, 18 and 19, respectively. The light sources are connected in parallel-by conductors 20 to the terminals of the base 12. Light source 14 is ofthe continuously energized or steady type and is illustratively shown ascomprising a carbon filament. A tungsten filament may, of course, besubstituted for the carbon filament shown. Light source 15 is of thetungsten filament type and is shown connected in series with abimetallic thermally responsive flasher switch 21 which lautomaticallyflashes the light source 15 from fully on to fully off at a repetitionrate of about two to six flashes per second. The on and oil times areabout equal. A ratio of on time to off should be in the range from 2:1to 1:2 for best results.

Light source 16 is a tungsten filament connected in series with afurther tungsten filament 22. A bimetallic flasher 23 periodically shortcircuits the further filament 22 thereby bringing light source 16 tofull brilliancy. With flasher 23 open, the temperature of light source16 may drop to a dull red or lower. The rate of rise to full brilliancyis accelerated by starting from a dull red temperature. The flasher 23may thus operate at a more rapid repetition rate than flasher 21 whichbrings light source 15 to a fully off condition.

The arrangement of FIG. 4 is similar to that of FIGS. 2 and 3 exceptthat the steady light source 24 is constituted by a tungsten filamentinstead of a carbon filament as for light source 14. Additionally, allthree light sources are enclosed in a common glass envelope 25. Thecommon envelope 25 is enclosed in a translucent flame-shaped covering 11as described above.

In operation, the steady light source 14 or 24 provides a predeterminedminimum illumination independently of the flashing sources 15 and 16.The flashing sources produce intermittent illumination which varies thetotal light output from the three sources as in the total light outputof a candle flame. By having two different repetition rates -for the twoflashing sources, the effect of a candle flame is further accentuated.The lateral spacing of the light sources produces an optical effectwhich simulates the lateral movement of a candle flame. Although one ofthe two flashing light sources may be omitted, a better simulation isobtained by the use of at least two flashing sources with differentrepetition rates. All of the flashin-g sources may be of the same type,such as the type of source 15 or source 16, if desired. The flame effectwill be obtained with the covering 11 omitted. Its use is desirable,however, because the translucency distorts the appearance of the lightsources and combines their illuminative effects in a manner whichstrengthens the optical illusion of an actual flame.

While I have shown and described what I believe to be the bestembodiments of my invention, it will be appa-rent to those skilled inthe art that various changes and modifications may be made thereinwithout departing from the spirit and scope of the invention as definedin the appended claims.

What is claimed is:

1. A flame-simulating illumination device for operation from a source ofvoltage comprising: a steady light source, first and second intermittentlight sources, a respective means for connecting said steady and saidfirst and second intermittent light sources in parallel to said voltagesource, said respective means connecting the first and secondintermittent light sources to the voltage source operating to vary theintensity of the output of each of said sources at a differentrepetition rate within the range from one to ten cycles per second Whilestill permitting current to pass through the steady light 4source at alltimes, said means for connecting the steady light source to the voltagesource operating the steady source continuously, and means for mountingall of said light 3 sources in close proximity to each other forsimultaneous observation by a user of the device, said device producinga visual flame-like effect.

2. A device according to claim 7, wherein said light diffusing means isa flame-shaped covering of translucent material at least partiallysurrounding all of said sources.

3. A device according to claim 2, wherein each of said sources isconstituted by an incandescent filament, said means for connecting saidintermittent sources to the voltage source each comprising thermallyactuated flasher means for varying the intensity of illumination of itsassociated filament.

4. A device according to claim 3 wherein one of said thermally actuatedasher means alternately connects and disconnects the filament of one ofsaid sources from the voltage source.

5. A device according to claim 3 wherein the filament of one of theintermittent sources is `formed of two parts and the flasher meansassociated with said one intermittent source periodically shorts out oneof the parts of said filament.

6. A device according to claim 4 wherein the filament of the other ofsaid intermittent sources is formed of two parts and the flasher meansassociated with said other source periodically shorts out one of theparts of said lament of said other intermittent source.

7. A device according to claim 1, further comprising 4 `light diffusingmeans common to and at least partially covering all of said lightsources.

8. A device according to claim 2, lucent material is a silicone rubber.

wherein said trans- References Cited UNITED STATES PATENTS 2,235,3603/1941 Davis 315-65 2,442,845 6/ 1948 Davis 315-72 2,760,120 8/ 1956Fisher-man 315-72 X 2,901,646 8/1959 Plagge et al. 313-31 2,976,4503/1961 Benoliel et al. 315-75 X 3,077,022 2/ 1963 Cullis 313-3153,138,737 6/1964- French 315-50 2,862,145 11/1958 Davis 315--473,218,500 11/1965 Wright 313-116 3,327,162 6/1967 Wright 315-473,047,773 7/ 1962 Morton 315-205 FOREIGN PATENTS 937,825 9/ 1963 GreatBritain.

JOHN W. HUCKERT, Primary Examiner.

A. I. JAMES, Assistant Examiner.

U.S. Cl. X.R.

